Commercial deep fat fryers may use gas or electricity as the heat source. The electric type fryer may utilize a fixed heating element or a swing-up heating element. Gas type fryers may utilize heat tubes or be of a broaster style fryer wherein the frypot is heated from the outside. Most fryers tend to use stainless steel or carbon steel for the cooking area. This apparatus and method may be utilized for any type of deep fat fryer and frypot material. The food cooking area is generally referred to as a frypot, although fry pan, vat, tub, etc. may be used.
Commercial natural gas or LP deep fat fryers generally have a stainless steel frypot for the cooking oil which has a “V-shaped” bottom portion (cool zone) and a rectangular top portion (fry zone). Most gas fired deep fat fryers have heat tubes which span the length of a rectangular shaped mid-portion. Such heat tubes allow for a large heat transfer area to heat the oil quickly. This produces a better tasting product with less oil absorption and faster recovery to desired temperature. The tubes are slightly above the V-shaped bottom, thus creating a relatively large cool zone. The cool zone allows heavily breaded crumbed foods such as onions, okra, mushrooms, chicken and fish to settle out. The large cool zone captures particles and holds said particles out of the fry zone and keeps them from carbonizing which reduces taste transfer to the cooking food. A tube-style frypot is more difficult to clean than an open frypot, but the tubes allow easy access to the heat source. Thus, regular cleaning and/or filtering is/are required including removal of the oil through a drain (generally near the bottom of the cool zone). Some other deep fat fryers have different configurations. An example is a broaster. They tend to have cylindrical sidewall frypot with a conical bottom. But they have issues analogous issues.
The enemies of frying oil are air, heat, moisture, food particles, trace metals and cleaning agents. Exposure to air oxidizes frying oil. Oil oxidizes faster at higher temperatures. Contact with moisture is considered the largest culprit in the deterioration of cooking oil. Food particles, as well as trace metals from chemicals or alloys that come in contact with frying oil, promote oxidation and polymerization by introducing both reactive and non-volatile compounds. Frequent filtration of the oil will reduce the negative effects of these contaminants. Caustic sodas and other chemical traces left over from cleaning agents also contribute to the early breakdown of frying oil.
Conventional cleaning methods include the following: Vacuum methods use large, robust, and expensive machines to vacuum the oil out of the fryer. This tends to also vacuum out non-oil components such as crumbs, and other food remnants. Many times this requires hiring a company that specializes in this process, which can add cost and complexity to keeping the fryers maintained. An alternative is for the owner of the fryer, or the owner's employees, attempt to clean the fryer by hand and refill it with oil. This raises issues about whether or not the owner or employee has the skill and tools to do an adequate job.
Another cleaning method is a mobile high pressure washer system which filters and pressure cleans the frypot using the recycled hot oil. The user will scrub the frypot with various tools while directing a spout or nozzle towards any particulates and rinsing said particulates towards the drain. Like the vacuum method, this method can be expensive and may require hiring the job out, and can have obvious safety concerns related to the hot oil splatter.
Another widely used cleaning method utilizes a chemical bath to clean the frypot. The oil is drained and the frypot is filled with water and a chemical solution is added. A minimum soak time is generally 2 hours to overnight. The frypot is then scrubbed and the solution drained. The frypot must then be thoroughly rinsed and dried. Other chemical solutions are sometimes brought to a boil before scrubbing can occur. This can also add expense, may require hiring out, and requires careful handling of chemicals.
Even with the above methods and systems sometimes debris along the inner walls or at the bottom of the V-shape remains. In that case, you still have to drain the oil and then try to scrape or remove particles. Typically a metal spatula might be used to try to scrape and disrupt the debris. However, the particles can congregate and be difficult to remove especially after the oil is removed. The particles are like sand and pebbles that have settled in a bucket. When the water is removed, the sand and pebbles remain. Only when the sand and pebbles are suspended in solution can they be poured from the bucket. It is difficult to reach all necessary areas and navigate around fryer structures like heat tubes and sensors embedded or mounted along the walls with spatulas or other kitchen utensils. And care must be taken not to scratch or abrade the fryer walls. There is room for improvement in this area.